


The secret history of Rosalba

by strawhat4life



Category: Teenage Mutant Ninja Turtles (TV 2012)
Genre: Experiments, F/M, OC, Other, TMNT
Language: English
Status: In-Progress
Published: 2015-09-26
Updated: 2015-09-30
Packaged: 2018-04-23 10:11:34
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 2,765
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4872841
Author URL: https://archiveofourown.org/users/strawhat4life/pseuds/strawhat4life
Summary: <blockquote class="userstuff">
              <p>Shredder's got a new plan to complete his revenge, the turtles will be in for a big surprise when they see this. (this is a story based on my tumblr rp account mutantxthieves WARNING: OC's involved/main character)</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> as said in the summary this is a story based on my OC character Rosalba from my tumblr blog Mutantxthieves I hadn't figured out her back story until recently thanks to some help from masterbrainturtle (follow this awesome donnie!) I only own Rosalba, the scientist, Nimue and Cooper.

Shredder’s scientists worked hard to try yet again make a replacement that would please him. Karai had betrayed him and he needed a new way to get to those turtles and Hamato Yoshi, what better way than to fight fire with fire?   
That’s what they were trying to create. With the right amount of turtle DNA and mutagen they would hopefully be able to create their own mutant turtle that would then be trained to battle with the turtles and allow him his revenge on Hamato Yoshi.

Shredder entered his lab that day and fear was thick in the air as the boss walked past them to the head scientist on the project, the man fearfully turned to him with the small rainbow turtle in his hands.  
Shredder’s piercing gaze fell on the terrified little man who had to use all of his strength to stop himself from shaking  
“Well?” the only word that left the boss’s mouth as the scientist swallowed the lump in his throat that sounded all too loud in the deadly silent room.  
“W-we think that we may have found something useful it’s um n-not a way to create the turtle y-yet but uh w-we may have found a way to progress it so that you can have your revenge faster.” The scientist said his voice quivering in fear Shredder didn’t move or say a word this told the scientist that hopefully he could continue

“It’s a growth serum, so that you won’t have to wait until the mutant is old enough to walk with the growth serum we should be able to accelerate the age by a number of years over night, we’re trying to discover a way to stop the growth serum once it starts though so that way we don’t over accelerate the growth, in a number of nights the mutant could die of old age.” The scientist explained to him to show the Shredder that he wasn’t completely useless he put the turtle back in its tank and then played a video of what happened when they had injected a rabbit with the growth serum in the course of three days it had grown and died of it’s age.  
“Rabbits have a short life however we predict that perhaps with a turtle the growth serum would take a week to work out.” The scientist said Shredder reached out and the man flinched until Shredder simply put his hand on the man’s shoulder  
“I want the antidote for the growth serum in a week; I hope you do not fail me for your sake.” Shredder turned and left them and a complete sigh of relief seemed to enter the room  
The scientist turned back to the baby turtle that was still in her tank, he put in a piece of lettuce for her to eat and rubbed his finger on her head gently   
“Hang in there Rosalba, we’ll have everything under control shortly.” He promised before turning back to his computer so that he could continue his work.


	2. Shredder's Experiment

**Summary for the Chapter:**

> Doctor Winch has run out of time to find the antidote for his serum, what's he going to do when the Shredder finds out?

**Notes for the Chapter:**

> again half the credit goes to Masterbrainturtle.tumblr.com for helping me think of it (through awesome rp skills!) I only own Winch, Rosalba, Nimue, and Cooper. enjoy!

The scientist looked to his little turtle nervously as the announcement was made that the Shredder was returning to the lab, the week was up and the growth serum antidote still hadn’t been done.  
“What am I gonna do Rosie?” he asked the little turtle as everyone scrambled around to get everything  in top shape so as to please the Shredder.

The little rainbow turtle just looked back at him before curling up in her shell, the man smiled  
“Yeah wish I could do that too.” He told her he heard the door open and the heavy footsteps approaching him. The scientist stood up ready to face the music as his boss made his way over to him

“Well?” Shredder asked how was it that one man could make that one word sound so utterly terrifying? The scientist swallowed hard  
“I-I don’t have it, some complications came up I just need a few more days I’m close to cracking it I promise you.” The scientist told him he knew this time by Shredder’s silence that this wasn’t good.   
“I’ve come up with a new formula but I just haven’t gotten to test it out yet I’m waiting for a subject to-“   
Shredder raised his hand and the scientist shut his eyes waiting for the Shredder to strike him but instead there was the sound of shattering glass, the scientists eyes shot open and he looked,   
Shredder had punched through the glass of the turtles cage and grabbed the scientists poor little rainbow turtle who was still curled up in her shell  
“Then what is this?”   
“That’s my pet Rosalba, she’s sort of my lucky charm I brought her for inspiration.” The scientist said Shredder glared and dropped the tiny turtle into the man’s hands  
“Run the experiment.”   
“But-“   
The Shredder sent the man a petrifying glare that shut him up instantly Shredder walked away and took a seat in a random chair that was sitting at a desk. The scientist looked down at his tiny turtle, which peeked out at him and sighed  
“I’m sorry Rosie; I just hope that my serum works right.” He told her stroking her head gently before he took her to the testing room, he set the turtle on the table and made what he hoped was the antidote to the growth serum he could feel the Shredder watching him from the observation room  
When all was ready the scientist clicked the record button on the camera and turned back to the Shredder  
“Experiment 56 testing the antidote, here we have a small rainbow turtle Rosalba, I will first inject her with the growth serum upon Shredder’s orders she must be about the same age as the other turtles so with the progression being about a year every fifteen minutes we will inject her with what we hope will be the antidote in seven and a half hours.” The scientist told the camera before he took the needle and injected it into the tiny turtle. From there he checked her vital signs every fifteen minutes to make sure the progression was working, he could feel the pressure as the Shredder stayed to watch the progression, only leaving for a few minutes each time before returning to check on the experiment.  
When time had finally come the scientist took the needle and looked at the turtle that wasn’t as tiny as she once was  
“Don’t let me down ok Rosie?” he asked her before he injected her with the antidote once again he checked her vital signs before looking back to the shredder and the camera

“We have now injected Rosalba with the antidote, in fifteen minutes I’ll check her to see if perhaps she has aged another year or so if the formula worked she should be stabilized at fifteen years old and we will move on to the mutation process.” He said before he took his seat and wrote down some notes.  
The fifteen minutes seemed more like fifty years, the scientist worried about his tiny little turtle who had been by his side since the start of this job watching him progress she was the only family he had and he just prayed that she would be alright. When the fifteen minutes were finally up he approached her and checked her vital signs, then he compared them to that of other rainbow turtles around her age that he had researched.

He had done it! The growth serum had stopped! To be sure he waited another fifteen minutes and checked again. They were the same! The man smiled relieved and turned back to the shredder  
“it worked! She’s stopped aging she’ll be alright!” he was so relieved but he knew that now came the tricky part. The mutation.

If Rosalba didn’t mutate to the right form, he and her were goners. But the scientist had a theory that he hoped would work. He held his little turtle to him as a few assistants brought in a tank of mutagen.  
The scientist stroked her head good naturedly  
“Alright, you’ve been lucky this far Rosie please don’t let me down. It’s up to fate this time but don’t let your luck run out this time.”   
With that he dropped her into the mutagen tank and stepped back. An eerie green glow began to form around the tiny turtle and soon the tank shattered, everyone backed away from the toxic goo that spilled out across the floor. When the scientist looked back he smiled at the form before him.  
A beautiful half human, half rainbow turtle lay on the floor before him with her legs curled up to her chest and her head tucked between her arms. Stepping carefully the scientist walked over to her and knelt down to her putting a gentle hand on her, the turtle flinched but he smiled  
“Rosalba?” she opened her violet eyes that were hidden under long lovely eyelashes up at him, her vision was blurred a bit but then she focused on the familiar face she didn’t know his name but she smiled a little none the less until the familiar heavy footsteps returned as Shredder made his way into the lab and her eyes clamped shut again. The scientist looked up to see the Shredder standing beside him  
“Well done Doctor Winch,” Shredder congratulated Winch smiled up at the Shredder before he smiled back down at Rosalba who peeked out again Winch helped her onto two feet carefully smiling as he saw the colors of the underside of her shell.  
“Tomorrow we start your training.” Shredder told her before he left again Winch looked back at her   
“Don’t worry, I won’t let anything bad happen to you Rosie.” He promised when he saw how scared she was. The scared mutant just nodded and followed him out. Tomorrow things would take a drastic change in the young turtle’s life.


	3. dangerous research

**Summary for the Chapter:**

> Winch wants to know more about Shredder's revenge. So he goes to the only person he knows will tell him the truth.

**Notes for the Chapter:**

> I only own Rosalba and Winch. no one else.

**Chapter three:**

 

Rosalba woke up the next morning to Winch shaking her gently awake

“Alright we’ve only got a little time before Shredder comes for your training, he’s going to train you physically so it’s my job to train you mentally.” He told her he sat beside her also handing her a bowl of salad, Rosalba took it the familiar vegetables making her smile at least something seemed to make her happy.  
“Alright so we’ll start with language, think you can talk?” Winch asked her Rosalba nodded   
“Yes,” she answered softly Winch smiled at her   
“Good, you’ll need to learn a few things for basics.” Winch told her he opened a book that was clearly meant for small children “We’ll start with reading, each letter makes a sound and each sound combined with that letter will form a word, when I show you a picture I want you to try and figure out the first sound of the word alright?” Winch asked her Rosalba nodded a bit

For about an hour the two went, Winch was impressed with how well she was taking to her lessons, learning quickly which sounds went with which letter until Shredder came to get her and begin her training.

Rosalba followed Shredder, Dr. Winch close behind her wanting to add everything to his research he set up a camera and sat on the side lines with a notebook, Winch was in charge of this project and since Rosalba was his turtle he wanted to be in on anything that was going on.

 

Things went on like this for a few days, Shredder would take Rosalba and train her first he worked on figuring out just how strong she was so they would have a starting point then they would move on to some smaller things though Shredder didn’t seem to have much patience for her messing up Winch had to step in now and then to keep the peace between the two. Then at night and in the morning before Shredder would arrive, Winch would teach Rosalba things she would need how to read, write and some manners. Many different things, sometimes he would take her down to the training area and have her test out a few weapons so he could figure out which ones she would do better in so he could report to Shredder and point him in the right direction of what she did best in.  
So far she seemed better with defensive weapons and long distance things such as throwing knives.   
Winch sighed when Rosalba was knocked down by one of the foot bots with a sword  
“Alright that’s enough.” Winch told the bot as he approached her and helped her up   
Rosalba looked at her feet ashamed that she had lost yet again but Winch smiled at her   
“Rosie it’s alright,” he told her he patted her head gently and she finally looked up at him  
“Swords aren’t your thing, that’s nothing to be ashamed of. Let’s take a look at some more long distance items alright?” he asked her Rosalba nodded as Winch walked over to the closet where the weapons were kept and began looking through until a sickle fell nearly hitting him. It gave him an idea,   
“Rose why don’t you try this?” he asked picking up the sickle with the chain attached and handed it to her after a quick explanation he stood back

She was a natural! Winch smiled relieved shredder would be pleased but…Winch wasn’t sure if he was going to be able to go along with Shredder’s plan for revenge on Hamato Yoshi, and using Rosalba to get it. Perhaps a little more research would work best? When Shredder took Rosalba for training that day, Winch decided to do a bit more research on these people that Shredder was so hell bent on revenge and he only knew one person to ask about that.   
Winch took a field trip down to what could only be described as the dungeon, he came face to face with the mutant that had caused Shredder to want his replacement so bad.  
“Karai?” he asked the snake looked up at him glaring Winch could only smile kindly at her  
“It’s alright; I’m just a friend I wanted to ask you about your father.” Winch explained to her Karai hissed angrily at him   
“He’sss not my father.” She replied   
“I’m sorry I didn’t mean Shredder, I meant Hamato Yoshi and his sons?” Winch asked her the glare only got further “please, this is for my ears only. Shredder had me create a mutant from my own turtle and-“  
Karai hissed at him again angrily causing him to jump a little this time  
“Mussst get turtle out of here.” Karai told him “Ssshredder will dessstroy her.”   
Winch swallowed the lump in his throat, Rosalba was his creation she was his child too.

“What about these turtles? Why does he want them gone?” Winch asked Karai suddenly hissed and backed away to the corner of her cell farthest from her door and it was then that Winch realized that they were no longer alone down here. Winch swallowed hard and turned around to face Rahzor standing behind him  
“Nosey doctors don’t get anywhere in this business Winch.” The mutant growled Winch knew that his trouble was only beginning then.

 

Rosalba was thrown go the ground again by Shredder this time harder than usual  
“Have you learned nothing?!” he shouted at her Rosalba whimpered softly as she sat up and a bit   
“I’m sorry sensai,” she apologized standing up their training was interrupted when Rahzor entered the room dragging Dr. Winch behind him Rahzor threw the scientist to the ground before Shredder’s feet  
“He was asking to many questions, asking about the Hamato Clan.” Rahzor growled Shredder stared at the man at his feet Winch didn’t dare meet the man’s gaze until Rosalba walked over to him   
“What’s the Hamato clan?’ she asked quietly Winch looked at Shredder then   
“She’s your replacement,” he said rather coldly Shredder glared at him before Shredder explained about what had happened between him and Hamato Yoshi, the truth which surprised Winch that he would tell her directly. 

“so…I’m just an attempt to replace Miwa-“  
“Karai.” Shredder snapped Rosalba physically flinched at the tone he used but nodded “Y-yes Karai.”

“You are more than that Rosalba, you are the Kunoichi that will help to avenge the foot clan and finally finish the Hamato clan.” Shredder told her Rosalba looked at Winch who still sat on his knees beside her before she looked back at Shredder then at the floor  
“And…what if I say no?”


End file.
